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The end of GRACE

19 December 2017

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The GRACE mission came to an end on 27 October. This joint mission of DLR and NASA measured the Earth's gravity field for fifteen years, much longer than the five years the satellites were expected to operate.

The two Gravity Recovery And Climate Experiment satellites were launched on 17 March 2002 and flew together in a low-altitude orbit using an innovative approach to study the Earth's gravity. The satellites measured the planet's mass, and the variations which occur over land and water at different heights.

Over time, scientists were able to study the data from the mission to observe changes in mass over the same locations and thus calculate the impact and concomitant changes to the gravity field. The data also has benefits for climate studies, such as monitoring changes in sea ice.

GRACE is part of ESA's Third Party Missions programme. This involves an agreement between ESA and DLR/NASA to process and distribute products generated from the satellite data.

You can download a range of GRACE products from our Data Access section.

Data acquired by GRACE was even used in combination with ESA's own GOCE mission - which came to an end in 2013 - to produce high precision maps of the Earth's gravity. You can learn more about this on the GOCE+ GeoExplore page.

After fifteen years of successful operation, the ageing batteries on board the satellites are failing and so scientists in Germany and the United States have agreed to end the mission. Though GRACE-2 is no longer operational and the mission is formally ended, the GRACE-1 satellite will continue to operate for several weeks while it is being made ready for deactivation. Due to their low orbit, the two satellites will descend and safely burn up in the atmosphere once their batteries are depleted.

With regards to the scientific return, after the loss of GRACE-2 the scientific teams are not able to derive nominal GRACE Level-2 gravity fields any more. The teams performed various manoeuvres during October on GRACE-1 which will help to better calibrate and understand the behaviour of the on-board accelerometer. This will enable the Release 06 reprocessing of the complete GRACE mission which will be the basis for continuation with the same standards and models that will be used in the GRACE Follow-on mission early next year.

GRACE satellitesArtist's concept of the twin GRACE satellites. Credits: NASA/GSFC